arch/microblaze/mm/pgtable.c

   1 /*
   2  *  This file contains the routines setting up the linux page tables.
   3  *
   4  * Copyright (C) 2008 Michal Simek
   5  * Copyright (C) 2008 PetaLogix
   6  *
   7  *    Copyright (C) 2007 Xilinx, Inc.  All rights reserved.
   8  *
   9  *  Derived from arch/ppc/mm/pgtable.c:
  10  *    -- paulus
  11  *
  12  *  Derived from arch/ppc/mm/init.c:
  13  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  14  *
  15  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  16  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  17  *    Copyright (C) 1996 Paul Mackerras
  18  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  19  *
  20  *  Derived from "arch/i386/mm/init.c"
  21  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  22  *
  23  *  This file is subject to the terms and conditions of the GNU General
  24  *  Public License.  See the file COPYING in the main directory of this
  25  *  archive for more details.
  26  *
  27  */
  28
  29 #include <linux/export.h>
  30 #include <linux/kernel.h>
  31 #include <linux/types.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/init.h>
  34
  35 #include <asm/pgtable.h>
  36 #include <asm/pgalloc.h>
  37 #include <linux/io.h>
  38 #include <asm/mmu.h>
  39 #include <asm/sections.h>
  40 #include <asm/fixmap.h>
  41
  42 unsigned long ioremap_base;
  43 unsigned long ioremap_bot;
  44 EXPORT_SYMBOL(ioremap_bot);
  45
  46 #ifndef CONFIG_SMP
  47 struct pgtable_cache_struct quicklists;
  48 #endif
  49
  50 static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
  51                 unsigned long flags)
  52 {
  53         unsigned long v, i;
  54         phys_addr_t p;
  55         int err;
  56
  57         /*
  58          * Choose an address to map it to.
  59          * Once the vmalloc system is running, we use it.
  60          * Before then, we use space going down from ioremap_base
  61          * (ioremap_bot records where we're up to).
  62          */
  63         p = addr & PAGE_MASK;
  64         size = PAGE_ALIGN(addr + size) - p;
  65
  66         /*
  67          * Don't allow anybody to remap normal RAM that we're using.
  68          * mem_init() sets high_memory so only do the check after that.
  69          *
  70          * However, allow remap of rootfs: TBD
  71          */
  72
  73         if (mem_init_done &&
  74                 p >= memory_start && p < virt_to_phys(high_memory) &&
  75                 !(p >= __virt_to_phys((phys_addr_t)__bss_stop) &&
  76                 p < __virt_to_phys((phys_addr_t)__bss_stop))) {
  77                 pr_warn("__ioremap(): phys addr "PTE_FMT" is RAM lr %pf\n",
  78                         (unsigned long)p, __builtin_return_address(0));
  79                 return NULL;
  80         }
  81
  82         if (size == 0)
  83                 return NULL;
  84
  85         /*
  86          * Is it already mapped? If the whole area is mapped then we're
  87          * done, otherwise remap it since we want to keep the virt addrs for
  88          * each request contiguous.
  89          *
  90          * We make the assumption here that if the bottom and top
  91          * of the range we want are mapped then it's mapped to the
  92          * same virt address (and this is contiguous).
  93          *  -- Cort
  94          */
  95
  96         if (mem_init_done) {
  97                 struct vm_struct *area;
  98                 area = get_vm_area(size, VM_IOREMAP);
  99                 if (area == NULL)
 100                         return NULL;
 101                 v = (unsigned long) area->addr;
 102         } else {
 103                 v = (ioremap_bot -= size);
 104         }
 105
 106         if ((flags & _PAGE_PRESENT) == 0)
 107                 flags |= _PAGE_KERNEL;
 108         if (flags & _PAGE_NO_CACHE)
 109                 flags |= _PAGE_GUARDED;
 110
 111         err = 0;
 112         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 113                 err = map_page(v + i, p + i, flags);
 114         if (err) {
 115                 if (mem_init_done)
 116                         vfree((void *)v);
 117                 return NULL;
 118         }
 119
 120         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 121 }
 122
 123 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
 124 {
 125         return __ioremap(addr, size, _PAGE_NO_CACHE);
 126 }
 127 EXPORT_SYMBOL(ioremap);
 128
 129 void iounmap(void __iomem *addr)
 130 {
 131         if ((__force void *)addr > high_memory &&
 132                                         (unsigned long) addr < ioremap_bot)
 133                 vfree((void *) (PAGE_MASK & (unsigned long) addr));
 134 }
 135 EXPORT_SYMBOL(iounmap);
 136
 137
 138 int map_page(unsigned long va, phys_addr_t pa, int flags)
 139 {
 140         pmd_t *pd;
 141         pte_t *pg;
 142         int err = -ENOMEM;
 143         /* Use upper 10 bits of VA to index the first level map */
 144         pd = pmd_offset(pgd_offset_k(va), va);
 145         /* Use middle 10 bits of VA to index the second-level map */
 146         pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
 147         /* pg = pte_alloc_kernel(&init_mm, pd, va); */
 148
 149         if (pg != NULL) {
 150                 err = 0;
 151                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 152                                 __pgprot(flags)));
 153                 if (unlikely(mem_init_done))
 154                         _tlbie(va);
 155         }
 156         return err;
 157 }
 158
 159 /*
 160  * Map in all of physical memory starting at CONFIG_KERNEL_START.
 161  */
 162 void __init mapin_ram(void)
 163 {
 164         unsigned long v, p, s, f;
 165
 166         v = CONFIG_KERNEL_START;
 167         p = memory_start;
 168         for (s = 0; s < lowmem_size; s += PAGE_SIZE) {
 169                 f = _PAGE_PRESENT | _PAGE_ACCESSED |
 170                                 _PAGE_SHARED | _PAGE_HWEXEC;
 171                 if ((char *) v < _stext || (char *) v >= _etext)
 172                         f |= _PAGE_WRENABLE;
 173                 else
 174                         /* On the MicroBlaze, no user access
 175                            forces R/W kernel access */
 176                         f |= _PAGE_USER;
 177                 map_page(v, p, f);
 178                 v += PAGE_SIZE;
 179                 p += PAGE_SIZE;
 180         }
 181 }
 182
 183 /* is x a power of 2? */
 184 #define is_power_of_2(x)        ((x) != 0 && (((x) & ((x) - 1)) == 0))
 185
 186 /* Scan the real Linux page tables and return a PTE pointer for
 187  * a virtual address in a context.
 188  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 189  * the PTE pointer is unmodified if PTE is not found.
 190  */
 191 static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
 192 {
 193         pgd_t   *pgd;
 194         pmd_t   *pmd;
 195         pte_t   *pte;
 196         int     retval = 0;
 197
 198         pgd = pgd_offset(mm, addr & PAGE_MASK);
 199         if (pgd) {
 200                 pmd = pmd_offset(pgd, addr & PAGE_MASK);
 201                 if (pmd_present(*pmd)) {
 202                         pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
 203                         if (pte) {
 204                                 retval = 1;
 205                                 *ptep = pte;
 206                         }
 207                 }
 208         }
 209         return retval;
 210 }
 211
 212 /* Find physical address for this virtual address.  Normally used by
 213  * I/O functions, but anyone can call it.
 214  */
 215 unsigned long iopa(unsigned long addr)
 216 {
 217         unsigned long pa;
 218
 219         pte_t *pte;
 220         struct mm_struct *mm;
 221
 222         /* Allow mapping of user addresses (within the thread)
 223          * for DMA if necessary.
 224          */
 225         if (addr < TASK_SIZE)
 226                 mm = current->mm;
 227         else
 228                 mm = &init_mm;
 229
 230         pa = 0;
 231         if (get_pteptr(mm, addr, &pte))
 232                 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
 233
 234         return pa;
 235 }
 236
 237 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
 238                 unsigned long address)
 239 {
 240         pte_t *pte;
 241         if (mem_init_done) {
 242                 pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 243         } else {
 244                 pte = (pte_t *)early_get_page();
 245                 if (pte)
 246                         clear_page(pte);
 247         }
 248         return pte;
 249 }
 250
 251 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 252 {
 253         unsigned long address = __fix_to_virt(idx);
 254
 255         if (idx >= __end_of_fixed_addresses)
 256                 BUG();
 257
 258         map_page(address, phys, pgprot_val(flags));
 259 }